Prior EMF shields have generally been designed to shield against high frequency fields in the range of frequencies typically associated with transformer or radio frequencies. Prior EMF shields generally surround either an EMF source to contain the field or surround a critical volume to isolate the volume from the field. Such typical prior EMF shields are disclosed in the following U.S. patents:
______________________________________ 4,012,706 Westendorp 4,156,862 Hansen 4,227,037 Layton 4,430,520 Tibbitts 4,484,171 McLoughlin 4,479,979 Krieger 5,025,489 Yamaguchi 5,066,937 Moran 5,241,132 McCormack 5,187,327 Ohta 5,402,323 Schwenk 5,483,423 Lewis 5,504,659 Acatay 5,566,055 Salvi 5,572,121 Beswick ______________________________________
Recently, concern has been arising over the effect of low magnitude low frequency magnetic fields such as typically arise from electrical wiring carrying AC current at around 50 to 60 hertz. Such fields are common in office buildings and similar structures where a considerable amount of wiring runs through a building structure to provide electrical power for equipment and lighting. In such applications, the extensive network of wiring makes it impractical to either shield the myriad of sources or to isolate the numerous critical volumes.
It is an object of the present invention therefore to provide an EMF shield which is effective against low magnitude, low frequency magnetic fields, which is easily installable in new installations or retrofittable to existing installations.
It is a further object of the present invention to provide an EMF shield effective against low magnitude, low frequency fields, without requiring containment of the field around a source or isolation of a critical volume.
It is a still further object of the present invention to provide an EMF shield in panel form which can be used to build an effective EMF shield wall.